Cargo items are often transported as containerized units in rectangular closed boxes measuring twenty feet long, eight feet wide, and eight feet high. Weight of a loaded cargo box can approach twenty tons. The present invention is directed to a transport vehicle of the truck or tractor-trailer type, having self-contained mechanism for loading large cargo boxes onto the vehicle bed (platform) at the point of departure, (e.g. a military depot or embarkation point) and unloading the boxes at the point of destination (e.g. a military field headquarters or troop staging area).
Vehicles of this general type are already known in the art; see for example U.S. Pat. Nos. 3,107,021 and 3,892,323. In some already known vehicles the cargo box is loaded onto the vehicle by backing the vehicle into a stationary position aligned with the box, lifting the front end of the box so that the box assumes a tilted position behind the vehicle, dragging the box forwardly over the rear edge of the vehicle platform, and tilting the box downwardly to a prone position on the vehicle platform.
The present invention is a departure from known practice in that the box is not dragged forwardly onto the platform of the vehicle; instead the front portion of the box is lifted upwardly, after which the vehicle is moved rearwardly so that the platform underlies the box; thereafter the box is tilted downwardly about its rest point on the platform so that the box assumes a prone position supported on the vehicle. The principle advantage of this arrangement is that the box does not have to be dragged onto the vehicle; wear and tear on the box is reduced. Also, the power mechanisms for handling the box need not be quite as powerful as with prior art arrangements because the box need only be tilted, not moved bodily along the ground during the initial box-loading step. Similar advantages are obtained during the box-unloading operation.
The mechanism of this invention is preferably designed to accomplish both loading of the box onto the vehicle platform (bed) and unloading of the box from the vehicle platform. The mechanism is particularly intended for use with military transport trucks or trailers adapted to go into remote areas where external loading-unloading equipment is not present or available.